Comparison of Treatment Planning on Dosimetric Differences Between 192Ir Sources for High-Dose Rate Brachytherapy
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초록
To evaluate whether the difference in geometrical characteristics between high-dose-rate (HDR) 192Ir sources would influence the dose distributions of intracavitary brachytherapy. Two types of microSelectron HDR 192Ir sources (classic and new models) were selected in this study. Two-dimensional (2D) treatment plans for classic and new sources were generated by using PLATO treatment planning system. We compared the point A, point B, and bladder and rectum reference points based on ICRU 38 recommendation. The radial dose function of the new source agrees with that of the classic source except difference of up to 2.6% at the nearest radial distance. The differences of anisotropy functions agree within 2% for r=1, 3, and 5 cm and 20°<θ<165°. The largest discrepancies of anisotropy functions reached up to 27% for θ<20° at r=0.25 cm and were up to 13%, 10%, and 7% at r=1, 3, and 5 cm for θ>170°, respectively. There were no significant differences in doses of point A, point B, and bladder point for the treatment plans between the new and classic sources. For the ICRU rectum point, the percent dose difference was on average 0.65% and up to 1.0%. The dose discrepancies between two treatment plans are mainly affected due to the geometrical difference of the source and the sealed capsule.
Abstract
To evaluate whether the difference in geometrical characteristics between high-dose-rate (HDR) 192Ir sources would influence the dose distributions of intracavitary brachytherapy. Two types of microSelectron HDR 192Ir sources (classic and new models) were selected in this study. Two-dimensional (2D) treatment plans for classic and new sources were generated by using PLATO treatment planning system. We compared the point A, point B, and bladder and rectum reference points based on ICRU 38 recommendation. The radial dose function of the new source agrees with that of the classic source except difference of up to 2.6% at the nearest radial distance. The differences of anisotropy functions agree within 2% for r=1, 3, and 5 cm and 20°<θ<165°. The largest discrepancies of anisotropy functions reached up to 27% for θ<20° at r=0.25 cm and were up to 13%, 10%, and 7% at r=1, 3, and 5 cm for θ>170°, respectively. There were no significant differences in doses of point A, point B, and bladder point for the treatment plans between the new and classic sources. For the ICRU rectum point, the percent dose difference was on average 0.65% and up to 1.0%. The dose discrepancies between two treatment plans are mainly affected due to the geometrical difference of the source and the sealed capsule.
참고문헌 (15)
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